The bidirectional dynamic relationship between physical exercise and interpersonal competence in college students: A four-wave longitudinal study

Interpersonal competence—the ability to initiate, maintain, and manage social relationships effectively—is essential for college students' academic success, psychological well-being, and future adaptability. Although physical exercise has been associated with improved social functioning, its bidirectional relationship with interpersonal competence remains underexplored.

The purpose of this study was to explore the dynamic relationship between physical exercise and interpersonal competence. A total of 455 Chinese university students (M_age = 23.54, SD = 1.70) participated in four monthly follow-ups from October 2024 to January 2025, corresponding to key academic phases: adaptation, stability, stress, and fluctuation. Participants completed the Physical Activity Rating Scale (PARS-3) and Interpersonal Competence Questionnaire (ICQ). Cross-lagged panel models (CLPM) and random intercept cross-lagged panel models (RI-CLPM) were applied to disentangle between-person and within-person effects. Results indicated that interpersonal competence variance was primarily explained by between-person stable traits (ICC = 0.799), whereas 74.6 % of physical exercise variability originated from within-person fluctuations. Significant bidirectional effects emerged during adaptation and stability phases, but non-significant associations were observed in stress and fluctuation phases. These findings offer new insights into the complex dynamics between physical exercise and interpersonal competence, highlighting the need for personalized interventions aligned with academic phases.